Source: kesslerandsons.com

(Helen) Why no serial? I suspect it might be one of the first ever made. Dave took these photos and had them posted the year before the MKX series was available to the public. This is just a guess on my part, but that's the only thing that half way makes sense to me.

This is the way Dave described the horn's specs on the company's website:

Julius Keilwerth MKX Tenor Sax
JK3000-8-0 | Gold Lacquer
 
Keilwerth MKX Tenor Sax Specifications
Country of Manufacture:  Made in Germany
Finish:  Gold lacquer (also available in Vintage Antique Finish)
Tone Holes:  Straight Holes
Range:  Low Bb – High F#
Body Material:  German Brass
Body Construction:  Single Post to Body
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